This section provides background information related to the present disclosure which is not necessarily prior art.
A circular piston bowl is commonly used in internal combustion engines wherein the piston crown itself forms the combustion chamber. The piston bowl controls the movement of air and fuel as the piston comes up for the compression stroke. The air and fuel swirl into a vortex inside the piston bowl before combustion takes place, creating a better mixture. By affecting the air/fuel mixture, better and more efficient combustion can be achieved, which leads to more power and optimized fuel economy.
The bowl rim is the higher temperature zone of the piston, due to the sharp edge effect and position in the combustion chamber. The concentration of thermo-mechanical fatigue brought on by alternate fatigue in tension and in compression can be in the bowl and on the bowl rim corresponding to the pin plane and thrust/antithrust plane in aluminum pistons. In steel pistons the concentration of oxidation formation occurs generally where the metal temperature is highest in the bowl and the on the bowl rim.
In order to mitigate the temperature and cooling of the piston, the piston bowl and the bowl rim, in some pistons an oil cooling gallery can be provided with enter/exit ports. The oil cooling flow is supplied from the bottom piston side, enters by inlet ports, circulates in the piston cooling gallery and exits from the outlet ports.
Accordingly, it is desirable to make the piston stronger in the bowl rim areas that are more critical due to high temperature fatigue mainly along the thrust/antitrust plane and pin plane with an optimal bowl rim shape and oil gallery shape/path in the pistons for an internal combustion engine.